The invention belongs to portable hand tools with power drive using for assembling and disassembling of threaded connections and can be used for mechanization of installation works in different branches of industry.
There is known an electrical vibration nut wrench, inventor""s certificate SU, A, 795927, consisting of the body with the handle, the power drive with the output shaft located inside, the connected with the latter planetary reduction gear containing the central cog-wheels with inner and outer cogs and the planet carrier with satellites, the elastically damping clutch, the power shaft connected through the latter to the central cog-wheel with inside cogs, the cog-wheel fixed on the end of the power shaft, the exciter of rotary oscillations containing the liner, debalanced shafts, located inside, with cog-wheels for linkage with the cog wheel fixed on the power shaft, and the spindle with the head for a wrench, mounted on its end.
The electrical vibration wrench, the inventor""s certificate SU, A, 967791, is additionally supplied with an ordinary free-wheel two-way clutch, the hoop of which is fixed strictly on the outer shaft of the drive""s rotor, the warpage fork is strictly connected to the planet carrier of the reduction gear and the hub of the sprocket wheel is fixed so that it can rotate relatively the outer shaft of the rotor and is connected to the warpage fork though the spiral spring.
Known nut wrenches have big weight and size, and their kinematic scheme does not allow to achieve the desired minimal rotating moment of constant sign that is required to screw down threaded connections.
It is known, by the Inventor""s certificate SU, A, 1771943, another vibration nut wrench. The wrench contains the body with the handle, the power drive with the output shaft and the exciter of rotary oscillations located inside. Into the body of the exciter of rotary oscillations there are placed debalanced shafts, the reduction gear and the spindle with the head for a wrench on its end. The spindle is strictly connected to the body of the exciter of rotary oscillations, and the reduction gear has cog-wheels with outer cogs mounted on the appropriate debalanced shaft, its cogs are in geared mesh with the cog-wheel with inner cogs, which is kinematically connected to the output shaft of the drive.
The shortage of the known wrench is the fact that its kinematic scheme does not allow to achieve the desired minimal rotating moment of constant sign at the control handle, under which screwing down of threaded connections is provided, because the exciter of rotary oscillations has sufficient turn-mass (debalanced shafts, heavy planet carrier) that is located at a long distance from the axis of rotation of the exciter.
The closest in its technical essence and the achieved effect, i.e., the prototype, is the vibration nut wrench by the RU, C1, 2081741 patent. The wrench contains the body with the control handle, inside it is located the power drive with the output shaft connected to the exciter of rotary oscillations and the spindle with with the head for a wrench on its end. The exciter of rotary oscillations is designed in the form of two fly-wheels connected to each other by the mechanism of variable speed of rotation and the planetary reduction gear. The carrier of the plabetary reduction gear is directly connected to the spindle of the wrench. When screwing a nut freely, the drive, through the mechanism of variable speed, turns the carrier of the planetary reduction gear that has far less mass than the fly-wheel. When the nut contacts the surface of the screwed detail, the carrier is stopped and the fly-wheel increase revolutions, putting in action the exciter of the rotary oscillations and tightening the threaded connection.
The construction of the known vibration nut wrench provides vibration oscillations of the exciter of rotary oscillations, under which the tightening torque will be more than the untightening torque. But the known nut wrench does not utilize energies of the fly-wheels because of faint difference between the amplitudes of vibration tightening and untightening torques. Besides, the known nut wrench does not allow to choose the most effective mode that minimizes the friction in thread.
The invention is based on the idea of increasing the amplitude difference of the shaft""s turning when screwing and unscrewing and, thus, achieve a greater total vibration screwing, torque and so to increase the effectiveness of the action of the vibration wrench.
The raised problem is solved in the vibration nut wrench containing the body with the control handle, the drive with the output shaft located inside, the exciter of rotary oscillations connected to it and made in the form of two fly-wheels connected to each other by the mechanism of variable speed of rotation and the planetary reduction gear with the carrier of the latter connected directly to the shaft of the wrench with the head for a wrench on its end, according to the proposed invention, by that the fly-wheel of the exciter of rotary oscillations, located on the side of the planetary reduction gear, is equipped with brake.
Use of the brake device in the proposed vibration nut wrench makes it possible to provide additional damping of the fly-wheel of the exciter of rotary oscillations located on the side of the planetary reduction gear. The brake arrangement can be as with variable, as with constant braking effort. As a result of all this the turn amplitude of the drive and the associated shaft in the unscrewing direction is decreased, while in screwing direction it grows up, i.e., the difference between them is increased, and the total vibration torque will be directed to screwing. The possibility of regulation of the amplitude of oscillations makes it possible to find out the most effective operating mode, achieving the minimal friction in thread. All this will increase the effectiveness of the vibration wrench.
Let""s consider a specific implementation of the vibration wrench on an example that does not, however, restrict the variety of its design.